Apparatus and method for the preparation of fluid bearing materials for surface analysis in a vacuum

Abstract

An apparatus and method for the presentation of organic samples at low temperature and under vacuum for analysis using a surface analysis technique is described. The apparatus carries a sample trapped between two hinged plates which is subsequently cryogenically-cooled and then inserted into a vacuum system where it locates on a cold stage. The device has a mechanism which is used to fracture the sample whilst under vacuum and open the two halves of the sample ready for analysis. It thus provides a reliable automated method of freeze-fracture, replacing current unreliable manual methods.

1 . An apparatus for the freeze-fracture and presentation for surface analysis in a vacuum of clean surfaces from frozen fluid containing materials, said apparatus incorporating;
 a pair of sample plates joined by a hinge pin to form a floating hinge; and   said plates being so disposed as to be able to face each other and also to be capable of rotating around said hinge pin with respect to each other; and   a means of support for the said sample plates suitable for insertion into a vacuum system; and   a means by which said sample plates can be mechanically prised apart in the vacuum; and   a means of opening the said hinged sample plates such that they rotate with respect to each other through a predefined rotation angle; and   a means of releasing said opening means inside the vacuum.   
   
   
       2 . An apparatus as claimed in  claim 1  where the said means of mechanically prising the sample plates apart in vacuum is an externally operated mechanical device. 
   
   
       3 . An apparatus as claimed in  claim 1  where the said means of prising the sample plates in vacuum is an electrical or electromagnetic device. 
   
   
       4 . An apparatus as claimed in  claim 1  where the said means of mechanically prising the sample plates apart in vacuum is the transfer probe. 
   
   
       5 . An apparatus as claimed in  claim 1  where the said means of opening said sample plates is a spring loaded bar. 
   
   
       6 - 7 . (canceled) 
   
   
       8 . An apparatus as claimed in  claim 1  where the said hinged sample plates and said sample holder are so arranged that after being prised apart and opened, the said sample plates lie at a predefined angle between 90 and 270 degrees with respect to each other. 
   
   
       9 . An apparatus as claimed in  claim 1 ; where the said hinged sample plates and sample holder are so arranged that after being prised apart, the said sample plates lie substantially in the same plane with both recently fractured sample surfaces facing substantially in the same direction. 
   
   
       10 . (canceled) 
   
   
       11 . An apparatus as claimed in and of  claim 1  where a single lever operates the fracture action and the release of the sprung action for opening the hinged plates. 
   
   
       12 . An apparatus as claimed in  claim 1  where the fracture and hinge opening mechanisms are both actuated by a single mechanical drive by either manual or automatic means. 
   
   
       13 . An apparatus as claimed in  claim 1  where all the materials of the said sample slides and said sample holder have a high thermal conductivity. 
   
   
       14 . An apparatus as claimed in  claim 1  where all the materials of the said sample slides and said sample holder are suitable for use in ultra high vacuum. 
   
   
       15 . (canceled) 
   
   
       16 . An apparatus as claimed in  claim 1  where samples of varying thicknesses between 0.001 mm and 2.5 mm can be accommodated between the sample plates. 
   
   
       17 . An apparatus as claimed in  claim 1  where the sample is contained within a well or indent formed on either sample plate. 
   
   
       18 . An apparatus as claimed in  claim 1  where multiple samples can be accommodated between the sample plates. 
   
   
       19 . An apparatus as claimed in  claim 1  where biological samples can be mounted for analysis in a SIMS instrument. 
   
   
       20 . An apparatus as claimed in  claim 1  where biological samples can be mounted for analysis in a surface analysis instrument. 
   
   
       21 . An apparatus as claimed in  claim 1  where the sample may be any organic sample. 
   
   
       22 . (canceled) 
   
   
       23 . A method for presentation of a frozen sample with minimised surface contamination and frosting for analysis using a surface analysis techniques comprising the steps of;
 placing a sample between a pair of hinged sample plates comprising an upper plate and a lower plate; and   applying pressure if required to ensure a good contact between the sample plates and the sample; and   rapidly freezing the sample plates containing the sample between them in a cryogenic bath in a dry gas environment: and   mounting the lower sample plate to a sample mount that is already immersed in the cryogenic bath by means of screws or clamps; and   setting the fracture mechanism; and   whilst still in the dry gas environment transferring the sample plate and sample mount assemblage to a cryogenically cooled stage in an insertion lock and placing it promptly under ultra high vacuum; and   freeze-cleaving the sample by mechanical means to separate the sample slides and opening them such that both the freeze-cleaved surfaces are facing in a direction suitable for surface analysis; and   transferring the sample holder assemblage to a second cryogenically cooled stage in the analysis position.   
   
   
       24 . A method for presentation of a frozen sample as claimed in  claim 23  where the rapidly freezing of the sample plates containing the sample between them in a cryogenic bath takes place outside of a dry gas environment and whilst the assemblage is still cooled in the cryogenic bath transferring them both to a dry gas environment. 
   
   
       25 . A method for presentation of a frozen sample as claimed in  claim 23  where the sample is any biological or biochemical material requiring freezing for surface analysis. 
   
   
       26 - 27 . (canceled)